The present invention relates generally to a rolling mill, and more particularly to rolling mills such as four-, three-, and two-roll rolling mills to roll wires and bars. The invention also relates to a roll-alignment adjusting device of the rolling mill.
In rolling bars or wires with a rolling mill, rolling of different sizes within a certain range can be accomplished by adjusting the rolling reduction, but without the range the rolling mill has to be retooled with rolls with a rolling groove of suitable size.
If an iron factory is to produce bars or wires of various sizes in small quantities, frequent change of rolls is inevitable, which consumes a lot of labor and time.
For example, as is shown in FIG. 18, the four-roll rolling mill proposed by us in the Japanese Unexamined Patent Publication, No. 275906/H 7 (1995), (prior art I) has five casings; i.e., a center casing 101, upper and lower casings 102 and 103, and a pair of right and left idle-roll brackets 104 and 105. Two roll units R1 each having one of the paired vertical rolls 1 and 1 and two roll units R2 each having one of the paired horizontal rolls 2 and 2 are so held in the five casings that the spacing between the rolls of each pair can be adjusted.
To change rolls of the four-roll rolling mill of the prior art I, oil-pressure operating nuts 107 threadedly engaging tie rods 106 are removed, the casings 102-105 are removed from the center casing 101, and the roll units R1 and R2 are extracted from the casings 102-105, as shown in FIG. 18. Then, in case of the roll units R1, as is shown in FIG. 19, the gear coupling 111, eccentric cartridge half 112, cartridge top plate 113, lock nut 114, bearing 115, the other eccentric cartridge half 116, taper sleeve 117, and driving roll 118 are removed. It is almost the same with the roll units R2 though they have a smaller number of parts.
The above work for the four roll units takes two persons eight hours, or 16 man-hours. Accordingly, the more frequent the roll change is, the more the productivity is reduced.
Besides, to reassemble the roll units, almost the whole of the above procedure has to be followed in the reverse order, which takes a lot of man-hours. The eccentric cartridges in particular make the reassembly and adjustment complicated. Once they are removed completely from the casings, the rolling reduction has to be adjusted from scratch; i.e., from the zero adjustment of each roll unit.
In case of a three- or two-roll rolling mill too, its disassembly and reassembly take a lot of man-hours, though in a different degree, for the same reasons.
On the other hand, disclosed in the Japanese Utility Model Publication, No. 10423/H 8 (1996), is a method for adjusting the roll alignment by inserting a shim or shims (thin plates to adjust the thickness) between each roll and the housing (prior art II). By this method, however, one has to assemble the rolling mill on one's estimate, measure the slippage in the alignment, disassemble the rolling mill, change shims, and repeats this series of work until the slippage is eliminated.
Furthermore, in the adjusting device disclosed in the Japanese Unexamined Patent Application, No. 16243/H 4 (1992), (prior art III) shown in FIG. 20, two boxes 212 are so mounted on an eccentric shaft 206 that one box 212 takes its position on one side of a roll 203; the other box, on the other side. A pin 218 is inserted, in parallel with the eccentric shaft 206, in each box 212, and one end of each pin 218 is pushed against the housing 202. An operating shaft 222 is so inserted in each box 212 that the operating shaft 222 and the pin 218 form a right angle and an eccentric protrusion 221 on the tip of the operating shaft 222 engages in the recess of the pin 218. The roll 203 is aligned with the pass line by turning the two operating shafts 222 to push and pull the pins 218 and thereby moving the two boxes 212 in parallel with the eccentric shaft 206.
In case of the above prior art II, one has to repeat the disassembly, measurement, and reassembly many times, which is very labour- and time-consuming.
In case of the above prior art III, the operating shafts 222 on both sides of the roll 203 require to be manipulated not only simultaneously but also in different ways; i.e., to manipulate one shaft to pull its pin and at the same time manipulate the other to push its pin, which is troublesome. It also poses a problem that if there remains even a slight gap between the pin 218 and the housing 202 on either side, there occurs a slippage immediately.
Moreover, it is needless to say that unless all the two, or three, or four rolls are completely aligned with the pass line, the rolled bar or wire is given a section of distorted circle, and the dimensional precision is also disturbed.
In accordance with the above, it is the primary object of the present invention to provide a rolling mill which is easy and quick to change rolls and quite simple and easy to adjust its rolling reduction.
It is another object of the present invention to provide a device to adjust the alignment of a plurality of rolls with a circumferential groove easily and precisely.
Furthermore, although we already proposed a rolling mill of a split housing type wherein the roll units are held between the two housing segments, in order to reduce the necessary man-hours for the disassembly and reassembly of the rolling units, make the roll change easy, and thereby increase productivity significantly, it is more object of the present invention to provide a roll-alignment adjusting device which prevents the roll alignment from being disturbed when such a split housing has been separated, and thereby enables a simpler, easier, quicker adjustment of roll alignment.